1. Field
The following description relates to a crystal oscillator of which reliability is improved, and a crystal oscillator package including the same.
2. Description of Related Art
A crystal oscillator is used for various applications such as a frequency oscillator, a frequency regulator, and a frequency converter. The crystal oscillator uses a crystal having excellent piezoelectric characteristics as a piezoelectric material. Here, the crystal serves as a stable mechanical vibration generator.
The crystal is artificially grown in a high pressure autoclave, is cut in relation to a crystal axis, and is processed to have desired characteristics of size and shape. Thus, the crystal is general manufactured in a wafer form.
In order to use a crystal wafer as the crystal oscillator, a crystal piece cut and processed from the crystal wafer should be fixed to an inner portion of a package, and an electrode should be formed on a surface of the crystal piece for the purpose of electrical connection.
In addition, the crystal piece fixed to the inner portion of the package may be adhered to the package by a conductive adhesive in order to be connected to external electrical elements.
In the crystal oscillator and the crystal oscillator package, when the electrode formed in the package and the crystal oscillator are adhered to each other by the conductive adhesive, adhesion between the electrode and the crystal oscillator becomes an important factor of reliability in harsh environments.
In the related art, a method of improving the adhesion by attaching an adhesive to a flat surface of an electrode pad of the crystal oscillator or forming a groove or a through-hole in the flat surface of the electrode pad has been used. However, in a method of increasing an adhesion surface area by forming the groove or the through-hole in the flat surface of the electrode pad, permeation of an adhesive was not easy due to a problem that an air film is formed in the groove or the through-hole.
Another method of improving reliability of the crystal oscillator and the crystal oscillator package has been desired.